The present invention generally relates to a keyboard, and in particular to the structure of a key or push button of the keyboard which allows efficient assembly and smooth movement of the push button.
Computer keyboards are a commonly used computer input device. A computer keyboard usually comprises a plurality of keys or push buttons arranged on a base. The push buttons are movably supported on the keyboard base whereby when the push buttons are struck and depressed, signals associated therewith are generated by a circuit and transmitted to a computer.
A conventional keyboard push button comprises a cap with a post extending downward therefrom. The post is axially and movably received in a bore defined in a base of the keyboard. The axial movement of the post may be adversely interfered with by non-perfect alignment of the post with the bore and tolerance thereof which cause jamming of the post and unstable movement of the cap. Also, noise caused by the unstable movement of the post and cap is a problem for the operation of the keyboard.
Furthermore, size reduction is a trend for the computer art. The conventional structure of a keyboard push button requires a post extending from a cap hindering reduction of the overall height of the keyboard.
A scissors-like double link mechanism is available in the market which comprises two link members pivoted to each other in a scissors-like manner for supporting a cap of a keyboard push button on a base of the keyboard. The scissors-like mechanism effectively solves the above problems. However, such a scissors-like mechanism requires pivotally attaching two link members together and mounting the links to both the cap and the base. This complicates assembly operation of keyboards.
Thus, it is desired to provide a push button structure of a keyboard having a scissors-like cap supporting mechanism which overcomes the problems encountered in the prior art.
Accordingly, an object of the present invention is to provide a push button structure of a keyboard which allows ready assembly thereof.
Another object of the present invention is to provide a push button structure of a keyboard which allows a smooth movement of the push button.
A further object of the present invention is to provide a push button structure of a keyboard which allows reduction of an overall height of the keyboard.
To achieve the above objects, in accordance with the present invention, there is provided a push button structure of a keyboard comprising a cap movably supported on a base plate by two link members which are pivotally attached to each other and pivotally attached to both the cap and the base plate. A rubber cone is arranged between the cap and the base plate whereby when the cap is depressed, the rubber cone is deformed to trigger a switching circuit for generating a signal associated with the depression of the push button. Pairs of projections are formed on the cap defining a gap between each pair for rotatably accommodating upper pivot pins of the link members. Each projection forms an inclined face opposing each other for guiding and facilitating insertion of the upper pivot pins therein. Tabs are stamped on the base plate and define spaces for rotatably accommodating lower pivot pins of the link members. The tabs form inclined edges for guiding and facilitating insertion of the lower pivot pins into the spaces thereof. One of the link members forms a central pivot which is rotatably received in a bore defined in the other link member. The bore has a diverging side opening for guiding and facilitating insertion of the central pivot into the bore thereby enhancing assembly of the push button.